Persistent network negotiation for peer to peer devices

ABSTRACT

A device may communicate with a peer-to-peer (P2P) network prior to associating with that network. The communications prior to association may include information about whether the P2P network is persistent or non-persistent. The information may include a persistent group intent field that identifies whether a device would prefer to join a persistent P2P network and allows a P2P network to advertise whether it is persistent.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/836,759 filed on Mar. 15, 2013 by Stephen McCann, et al. entitled,“Persistent Network Negotiation for Peer to Peer Devices”, which claimspriority U.S. Provisional Application No. 61/761,576, filed on Feb. 6,2013, entitled “Persistent Network Negotiation for Peer to PeerDevices,” both of which are incorporated herein by reference as ifreproduced in their entirety.

BACKGROUND

Wireless network deployments, such as wireless local area networks(“WLANs”), allow mobile devices to access network and Internet serviceswhen within proximity of wireless communication signals of thosewireless networks. Peer-to-peer (“P2P”) networks allow connectivitybetween individual devices. In one example, a P2P network may bereferred to as a group and include a group owner (GO) that is the masterdevice for the group that may manage signaling, timing, clocksynchronization, etc., and establish certain group settings (e.g., thegroup may be set as a persistent group or a non-persistent group). Anon-persistent group only lasts (i.e., remains intact as a group) aslong as a device is in communication range of the group and otherdevices within the group. A non-persistent group treats a device thatwants to re-join as if the device is a new device joining the group forthe first time. In contrast, a persistent group is a group in which thegroup owner and/or other devices within the group are able to storepersistent information related to the group. In other words, the term“persistence” when used in reference to a persistent or a non-persistentgroup implies the ability (or lack of ability) of a group owner and/orgroup member to store information associated with that group as well asinformation associated with the devices that join the group. Therefore,information for joining the group may persist (i.e., remain stored)within a device for a persistent group. In one embodiment, the P2Pnetwork may utilize either wireless fidelity (Wi-Fi) or Wireless LAN(WLAN) between wireless devices. For example, the Wi-Fi Alliance (WFA)established guidelines for peer to peer connectivity between Wi-Fienabled devices that is referred to as “Wi-Fi Direct” and outlined inthe Wi-Fi Peer-to-Peer (P2P) Technical Specification from 2010.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a communication network;

FIG. 2 illustrates candidate devices in communication;

FIG. 3 illustrates candidate devices forming a group;

FIG. 4 illustrates an alternative communication network;

FIG. 5 illustrates a communication layer architecture;

FIG. 6 illustrates a wireless device (“STA”);

FIG. 7 illustrates a process for a wireless device discovering a P2Pgroup;

FIG. 8 illustrates a process for handling a device in a persistentgroup;

FIG. 9 illustrates a process by which a group owner determinespersistence;

FIG. 10 illustrates a process for by which a group owner decidespersistence;

FIG. 11 illustrates a process for determining a group owner;

FIG. 12 illustrates a process for advertising whether persistence isenabled for a group; and

FIG. 13 illustrates a process for a wireless device discovering P2Pgroups.

DETAILED DESCRIPTION

The disclosed systems and methods allow mobile devices or wirelessdevices to communicate with a peer-to-peer (P2P) network or group priorto negotiating which device will become group owner (“group ownernegotiation”) of that P2P network. The communications prior to groupowner negotiation may include information about whether the P2P networkor group is persistent or non-persistent. The information may include apersistent group intent field that identifies whether a device wouldprefer to join a persistent P2P network or group and allows a P2Pnetwork or group to advertise whether the P2P network or group ispersistent.

The communication between a wireless device and a P2P network/group maybe through Wi-Fi or WLAN protocols. The wireless device and a group (ora group owner) may communicate prior to the wireless device joining thegroup. These communications that occur prior to the device joining thegroup are preceded by a discovery phase, which may include discoverycommunications or discovery information, and is followed by associationcommunications in which a device associates with the group after joiningthe group. Group owner negotiation may be part of the joining process. Apersistent group intent (PGI) field may be communicated prior to adevice joining a particular group.

Wireless or mobile devices that communicate prior to joining a group mayinclude mobile communication devices, mobile computing devices, fixedcomputing devices, or any other device capable of communicatingwirelessly with a wireless network. Such devices may also be referred toas terminals, mobile devices, stations (“STA”) or user equipment, andmay also include mobile smart phones (e.g., a BlackBerry® smart phone,BlackBerry® Playbook or BlackBerry® Mobile Computer), wireless personaldigital assistants (“PDA”), machine to machine equipment, equipmentwithin a smart grid (“SmartGrid”), printers, displays, equipment withina mesh network (an ad-hoc or peer network),laptop/tablet/notebook/netbook computers with wireless adapters, etc.FIG. 4 illustrates one embodiment of a mobile device or terminal.

As described, a P2P network or group may include one or more wirelessdevices. The connection for the network or group may be through awireless network such as with WLAN protocols. In one embodiment, a groupmay be established for certain devices connected to a WLAN. Inalternative devices, the devices may discover information about othernetworks/groups through other protocols and architectures, including acellular network or a WiMax network. The group may be part of a networkwhich may further comprise a publicly accessible network, such as theInternet, a private network, such as an intranet, or combinationsthereof, and may utilize a variety of networking protocols now availableor later developed including, but not limited to TCP/IP based networkingprotocols. The networks may include any communication method or employany form of machine-readable media for communicating information fromone device to another.

FIG. 1 illustrates a communication network. A wireless device 102 maycommunicate with one or more P2P groups. A P2P network may also bereferred to as a P2P group or just a group throughout this disclosurefor simplicity. A group may refer to a P2P group comprising a groupowner (GO) and one or more devices associated with the GO. The wirelessdevice 102 may also be referred to as a P2P device and is furtherdescribed below with respect to FIG. 4. FIG. 1 illustrates a first P2Pgroup 104 and a second P2P group 106 that communicate with the wirelessdevice 102. In alternative embodiments, there may be more or fewergroups for a wireless device to connect with.

The communications may be pre-joining, which means that the wirelessdevice 102 has not joined one of the groups 104, 106, but stillcommunicates with the groups prior to joining. Likewise, thecommunications may be pre-association, which means that the wirelessdevice 102 is not associated with one of the groups 104, 106, but stillcommunicates with the groups prior to association. The communicationsmay be at any stage of the group pre-association process, includingwhere the wireless device 102 has not yet joined a group and/or wherenegotiation with the GO are not complete, and may further include a findphase, scan phase, and/or the time period when the wireless device 102is in a listen state.

Through pre-joining communications, the wireless device 102 may retrieveinformation about the available groups 104, 106. Likewise, the wirelessdevice 102 may transmit information about potential features requiredfor the wireless device 102 to connect with (or join) a particulargroup. The communications illustrated and described below aretransmitted before the wireless device 102 joins a particular group.Those communications (i.e., the pre-joining communications) may also bereferred to as discovery communications. In one embodiment, thepre-joining communications may include information about a persistentstate of the groups 104, 106. Likewise, the wireless device 102 maycommunicate its preferences regarding joining a persistent ornon-persistent network.

Persistency refers to whether a group is set as a persistent group or anon-persistent group. A persistent group is a P2P peer group with agroup owner (GO) and other devices are able to store persistentinformation specifically related to that group. In a persistent group,the GO and other devices of that group store persistent information(e.g. credentials, group owner identity, etc.) in order to form apersistent P2P group (PPG). The credentials may include encryption keys,identifiers, or other information. The PPG may terminate because adevice is disconnected from the group, as a result of a positive actionwithin the group, or if the GO and the device lose mutual connectivity(e.g. a reduction in signal strength or quality results due to a radiofade or interference). If one of the devices previously connected to thePPG re-discovers the same PPG, it may use its stored persistenceinformation (e.g. credentials) to re-connect to the PPG. Since thecredentials were stored, the device may omit some or all of thenegotiation and/or authentication steps in the process of re-joining thePPG. Conversely, an attempt by a device that was previously connected toa non-persistent group to re-connect with that non-persistent groupincludes the entire negotiation/authentication process as if the devicewas never previously connected with the group. In other words, the term“persistent” with regards to whether a group is persistent ornon-persistent equates to the ability (or inability) of a group ownerand/or group member to store information associated with that group aswell as information associated with the devices that join the group.

Accordingly, FIG. 1 illustrates that pre-joining information may betransmitted between a device and a group (or GO) while the device isdeciding whether to join the group. Previously, persistency informationwas only transmitted to/from a candidate device once that candidate wasconnected with a group. In one embodiment, the communication ofinformation (e.g., a persistent group intent (PGI) value) regardingpersistency may be transmitted as part of a Persistent Group Intent(PGI) field. The PGI value may indicate whether a device intends (i.e.,possesses an intent) to store persistent P2P group (PPG) informationand/or a desire that the group (when established) uses persistence. ThePGI value may be part of a connection capability field: as shown inTable 1 below:

TABLE 1 Connection Capability Field Bit Information Notes 0 New Set to 1indicates that the device can be either Client or GO. Otherwise, set to0. 1 Client Set to 1 indicates that the device is a Client or may beClient only. Otherwise, set to 0. 2 GO Set to 1 indicates that thedevice is a GO or may be GO only. Otherwise, set to 0. 3 Persistent Whentransmitted by a device which has not yet Group Intent joined a groupand/or where GO negotiation is not (PGI) complete. The device may be inthe find phase, scan phase or in the listen state. Set to 1 indicatesthat the device: 1) intends to store persistent group information if itbecomes GO of the group; and 2) that it wishes the group to bepersistent. When transmitted by a device in an established group, set to1 indicates that persistence is enabled within the group. Otherwise, setto 0 by a device in an established group to indicate that persistence isnot enabled within the group. 4-7 Reserved —

The PGI bit field which includes a PGI bit set to the PGI value may betransmitted prior to P2P group association or prior to a device joiningthe group. A device sets the PGI value of a PGI bit within the PGI fieldto 1, in the Connection Capabilities Attribute to indicate that thedevice intends to store persistent information (e.g. credentials) when aP2P group is established. If a device sets the PGI value to 0, thedevice is not intending (i.e., lacks the intent or does not possess theintent) to store persistent information. Alternative bits and/or fieldsmay be used to convey the intent or lack of intent of a device to storepersistent information including a PGI value which may be transmitted inan attribute other than the connection capability field as illustratedin the example of Table 1. In particular, the signaling described inthese embodiments may be incorporated in any existing or new frame,which may be transmitted or received by a device prior to joining agroup.

FIG. 2 illustrates candidate devices in communication. A first candidatedevice 202 communicates with a second candidate device 204. Thecandidate devices 202, 204 may be examples of the wireless device 102that are not connected to the network and may be further described withrespect to FIG. 6. The communications between the candidate devices 202,204 are prior to either device joining a group. In one embodiment, thecommunications may include persistence information (e.g. PGI bit) thateither candidate device 202, 204 may use in deciding to establish agroup and deciding whether the group will be persistent or not.

FIG. 3 illustrates candidate devices forming a group. In particular, thecandidate devices 202, 204 of FIG. 2 (after their pre-joiningcommunications) can form the P2P group 302 as shown in FIG. 3. Thepre-joining communications may include persistence information that isused for determining whether the group 302 should be persistent or not.In addition, persistence information may be used for determining whichdevice should be the group owner (GO). In one embodiment, when one ofthe candidate devices 202, 204 desires a persistent group, that deviceis the GO for a persistent group. The other device (not desiring apersistent group) can still join the persistent group, but may choosenot to save information regarding the group. A GO intent level(discussed with respect to FIG. 7) may also be used in identifying theGO.

FIG. 4 illustrates an alternative communication network. In particular,a P2P group 406 (which may be either of the P2P Groups 104, 106 fromFIG. 1 or group 302 from FIG. 3) may include the wireless device 102from FIG. 1, in addition to a group owner (GO) 404. A candidate device402 may engage in pre-joining communications with the group 406. Thecandidate device 402 may be either of the candidate devices 202, 204 andmay also be the wireless device 102 as described with respect to FIG. 6.As discussed above, the communications may include persistenceinformation indicating whether the group 406 is persistent ornon-persistent, such as with the PGI bit. In one embodiment, the GO 404and candidate device 402 are wireless devices as with the wirelessdevice 102 and as further described below with respect to FIG. 6.

The candidate device 402 may be a device which is capable of receivingadvertisements (e.g., an advertisement including a PGI bit associatedwith the group 406) from another peer device (including a GO, such as GO404) during pre-joining or discovery communications. The candidatedevice 402 may not be connected to a group during these communicationsand negotiations. In one example, the candidate device 402 may desire tojoin a persistent network, but during pre joining or discoverycommunications with the group 406, the candidate device 402 maydetermine, based on a value of a PGI bit received from the GO 404, thatpersistence is not enabled within the group 406, and the candidatedevice 402 may then decide to decline to join the group 406. Thecandidate device 402 may then attempt to find and join an alternativenetwork which the candidate device 402 determines to be persistent. Inother implementations, the candidate device 402 desiring to join apersistent network may decide to join the group 406 even afterdetermining that persistence is not enabled within the group 406. In oneembodiment, the group 406 (or the GO 404 on behalf of the group 406)advertises (e.g., broadcasts, unicasts, or multicasts) the persistenceinformation (e.g., a PGI bit having a PGI value) to device(s) withincommunication range of the group 406.

FIG. 5 illustrates a communication layer architecture 500. Thecommunication layer architecture 500 includes seven layers which may beimplemented in accordance with the Open Systems Interconnection (“OSI”)Reference Model. The communication layer architecture 500 includes adata link layer 502, which includes a media access control (“MAC”)sub-layer 504. The MAC sub-layer provides addressing and channel accesscontrol mechanisms that make it possible for several devices or networknodes to communicate within a multiple access network that incorporatesa shared medium, e.g. Ethernet. The hardware that implements the MAC maybe referred to as a medium access controller. The MAC sub-layer acts asan interface between the logical link control (“LLC”) sub layer and thenetwork's physical layer. The MAC layer emulates a full-duplex logicalcommunication channel in a multi-point network. This channel may provideunicast, multicast or broadcast communication service.

Wireless devices (e.g., the wireless device 102 of FIG. 1 or thecandidate devices of FIGS. 2-4) may communicate prior to joining a group(i.e. pre-joining communications 506). The inclusion of pre-joiningcommunications 506 on the MAC sub-layer 504 may allow for a mobiledevice to communicate with a group or other devices before joining agroup. In particular, the persistence information that is advertisedduring pre-joining communications 506 may be exchanged at the MACsub-layer 504. A wireless device may access information from a memory orother hardware of the mobile device at the MAC sub-layer 504 withoutneeding to perform operations at or above an internet protocol layer(e.g., a network layer 508) and without needing to provide access to theinternet protocol layer. Low-level resource operations at the MACsub-layer require relatively fewer system resources thanuser-interface-intensive and operating system intensive operations(e.g., web-browser operations) at an application layer.

FIG. 6 illustrates a wireless device (“STA”) 102 as shown in FIGS. 1 and4. The wireless device 102 shown in FIG. 6 may also be any of thecandidate devices shown in FIGS. 2-4, but is referred to throughout aswireless device 102 for simplicity. The wireless device 102 includes aprocessor 602 that may be used to control the overall operation of thewireless device 102. The processor 602 may be implemented using acontroller, a general purpose processor, a digital signal processor,dedicated hardware, or any combination thereof. The processor 602 mayinclude a central processing unit, a graphics processing unit, a digitalsignal processor or other type of processing device. The processor 602may be a component in any one of a variety of systems. For example, theprocessor 602 may be part of a standard personal computer or aworkstation. The processor 602 may be one or more general processors,digital signal processors, application specific integrated circuits,field programmable gate arrays, servers, networks, digital circuits,analog circuits, combinations thereof, or other now known or laterdeveloped devices for analyzing and processing data. The processor 602may operate in conjunction with a software program, such as codegenerated manually (i.e., programmed).

The wireless device 102 also includes a terminal message generator 604and a terminal data parser 606. The terminal message generator 604 maygenerate discovery messages such as the pre-joining communications shownin FIGS. 1-4. The terminal data parser 606 may be used to retrievenetwork information from memory (e.g., random access memory 610, etc.).For example, the terminal data parser 606 may request discoveryinformation (e.g. persistent state information for one or more groups)from a network/group.

In the illustrated embodiment, the terminal message generator 604 andthe terminal data parser 606 are shown as separate from and connected tothe processor 602. In alternative embodiments, the terminal messagegenerator 604 and the terminal data parser 606 may be implemented in theprocessor 602 and/or in a wireless communication subsystem (e.g., awireless communication subsystem 618). The terminal message generator604 and the terminal data parser 606 may be implemented using anycombination of hardware, firmware, and/or software. For example, one ormore integrated circuits, discrete semiconductor components, and/orpassive electronic components may be used. For example, the terminalmessage generator 604 and the terminal data parser 606, or partsthereof, may be implemented using one or more circuits, programmableprocessors, application specific integrated circuits, programmable logicdevices, field programmable logic devices, etc.

The terminal message generator 604 and the terminal data parser 606, orparts thereof, may be implemented using instructions, code, and/or othersoftware and/or firmware, etc. stored on a machine accessible medium andexecutable by, for example, a processor (e.g., the processor 602). Theterminal message generator 604 or the terminal data parser 606 may bestored on or include a tangible storage medium or memory. For example,the terminal message generator 604 or the terminal data parser 606 maybe implemented in software stored on a memory that is executable by theprocessor 602. Alternatively, the terminal message generator 604 and/orthe terminal data parser 606 may be implemented in hardware withsoftware functions. The memory for storing software associated with theterminal message generator 604 and/or the terminal data parser 606 mayinclude, but is not limited to, computer readable storage media such asvarious types of volatile and non-volatile storage media, includingrandom access memory, read-only memory, programmable read-only memory,electrically programmable read-only memory, electrically erasableread-only memory, flash memory, magnetic tape or disk, optical media andthe like. In one embodiment, the memory may include the random accessmemory 610 for the processor 602, or may be an external storage deviceor database for storing recorded ad or user data. Examples include ahard drive, compact disc (“CD”), digital video disc (“DVD”), memorycard, memory stick, floppy disc, universal serial bus (“USB”) memorydevice, or any other device operative to store user data. The memory isoperable to store instructions executable by the processor 602.

The wireless device 102 may include a FLASH memory 608, a random accessmemory 610, and/or an expandable memory interface 612 coupled with theprocessor 602. The FLASH memory 608 may store computer readableinstructions and/or data. In some embodiments, the FLASH memory 608and/or the RAM 610 may store the discovery communications 120 (serviceinformation) from FIG. 1 and instructions for communicating thatinformation. The processor 602 may be coupled with the memory (e.g. theFLASH memory 608, or the RAM 610) for storing software instructionsexecutable by the processor 602. The memory may include, but is notlimited to, computer readable storage media such as various types ofvolatile and non-volatile storage media, including random access memory,read-only memory, programmable read-only memory, electricallyprogrammable read-only memory, electrically erasable read-only memory,flash memory, magnetic tape or disk, optical media and the like. Thefunctions, acts or tasks illustrated in the figures or described hereinmay be performed by the programmed processor 602 executing theinstructions stored in the memory. The functions, acts or tasks areindependent of the particular type of instruction set, storage media,processor or processing strategy and may be performed by software,hardware, integrated circuits, firm-ware, micro-code and the like,operating alone or in combination. Likewise, processing strategies mayinclude multiprocessing, multitasking, parallel processing and the like.

The wireless device 102 may include a security hardware interface 614 toreceive a SIM card from a wireless service provider. A SIM card may beused for service discovery communications including authentication ofthe wireless device 102 for establishing a connection with aWLAN-supported network. The wireless device 102 may be provided with anexternal data I/O interface 616. The external data I/O interface 616 maybe used by a user to transfer information to the wireless device 102through a wired medium.

The wireless device 102 may include wireless communication subsystem 618to enable wireless communications with other devices or with a P2Pgroup/network. Although not shown, the wireless device 102 may also havea long-range communication subsystem to receive messages from, and sendmessages to, a cellular wireless network. In the illustrated examplesdescribed herein, the wireless communication subsystem 618 can beconfigured in accordance with the IEEE® 802.11 standard. In otherexample implementations, the wireless communication subsystem 618 may beimplemented using a BLUETOOTH® radio, a ZIGBEE® device, a wireless USBdevice, an ultra-wideband radio, a Near Field Communications (“NFC”)device, or a Radio Frequency Identifier (“RFID”) device.

The wireless device 102 may include a user interface for communicatingto/from the device. The user interface may be separate component or itmay include a speaker 620, a microphone 622, a display 624, and a userinput interface 626. The display 624 may be a liquid crystal display, anorganic light emitting diode, a flat panel display, a solid statedisplay, a cathode ray tube, a projector, a printer or other now knownor later developed display device for outputting determined information.The user input interface 626 may include alphanumeric keyboard and/ortelephone-type keypad, a multi-direction actuator or roller wheel withdynamic button pressing capability, a touch panel, etc. The P2Pdiscovery information that is communicated with a network prior toconnection may be communicated with or without each of the userinterfaces described herein. The speaker, 620, the microphone 622, thedisplay 624, the user input interface 626, and/or any combinationthereof may be omitted in alternative embodiments. In one embodiment,the wireless device 102 is a battery-powered device and includes abattery 628 and a battery interface 630.

FIG. 7 illustrates a process for a wireless device discovering a P2Pgroup. A candidate device (e.g. the candidate devices in FIGS. 2-4)determines which type of group the candidate device would like (prefer)to join as in block 702. The determination regarding which type of groupthe candidate device desires (intends) to join may include determiningwhether the candidate device desires to join a persistent group or anon-persistent group. This determination in block 702 may be made inresponse to one or more of the following five indications.

First, an application specific indication (e.g. exposed at anApplication Programming Interface (API)) or the identity, nature, and/ortype of an application may be considered in the determination as towhether the group which the candidate device joins should or should notbe persistent. As such, the determination of whether the candidatedevice desires to join a persistent group or a non-persistent group ismade based on the application(s) (or signaling from the application(s)).In some implementations, the application(s) (or signaling from theapplication(s) may in fact trigger the P2P group discovery process.

Second, there may be a user-provided input (e.g. the user is given achoice prior to joining the group or the user/administrator may be ableto configure settings within the device, etc.) regarding the desire forgroup persistence. The input may be provided via a User Interface (UI)on the device, and may be pre-configured or be configured remotely.

Third, there may be a service-specific indication (e.g. for Wi-Fi DirectServices (WFDS) or IEEE 802.11aq—Pre Association Discovery (PAD)). Forexample, the candidate device may determine based on a service, servicetype, or service identifier, that the candidate device desires that agroup be persistent. As one example, joining a group may be for thepurposes of accessing a service, such as a printing service.

Fourth, the determination regarding which type of group the candidatedevice would like to join may be triggered based on hardwareconfiguration. The determination may depend on the state of othercommunications protocols in the candidate device. For example, whenassociated with a Bluetooth pairing connection, the candidate device maydetermine that group persistence should be used. As another example,when establishing a connection in response to a near-fieldcommunications (NFC) procedure, the candidate device may determine thatpersistence should not be used.

Fifth, the determination may be location-specific and therefore based onlocation information such as Global Positioning System signals or data(GPS), a cellular network cell ID or country code, or IEEE 802.11location information or country code. The candidate device may determinethat any group the device joins should or should not be persistent ifthe user is at a home location, or a location where a previous oralternative determination (e.g. user-provided input) indicated a desirefor the use (or desire for no use) of PPGs.

Rules governing one or more of the candidate device's preferences listedabove may be described by one or more group persistence policies thatare set (i.e., configured) on the candidate device, which may be set bythe user, an administrator, or any other third party with rights to doso. Following the determination in block 702, the candidate device maytake different actions depending on whether the candidate device hasdetermined that it should connect, or desires to connect, to either apersistent P2P group (PPG) or a non-persistent-P2P group (non-PPG) inblock 704. If the candidate device's desire (or requirement,determination, or policy) is for a PPG, the candidate device indicatesthis request in signaling or communications sent prior to groupformation (e.g. by setting the value of the PGI bit to 1 in block 706).The candidate device subsequently proceeds with group discovery usingthe value of the PGI bit set to 1 in block 706. In block 708, there maybe an optional intent level that provides an objective measure of acandidate device's desire or ability to be a GO for a group. A desire tobe part of a persistent group results in an increase intent level forthat device upon joining a persistent group. If the desire is for anon-PPG, the candidate device sets the value of the PGI bit to 0 as inblock 710 and proceeds with group discover. In block 712, the intentlevel is optionally decreased because the device desires to join anon-persistent network.

Optionally, the communications or signaling for the determination inblock 702 may allow for a distinction to be drawn between a devicewhich: 1) desires the use of persistence; 2) desires that persistencenot be used; 3) has no preference on whether or not persistence shouldbe used; 4) has a policy to not join (or not remain in) any group unlesspersistence is enabled; and 5) has a policy to not join (or not remainin) any group unless persistence is disabled. Subsets or supersets ofthe above scenarios are also possible.

In an alternative embodiment, a device indicating a desire and/or policyto join a group with persistence enabled may, in response to determiningthat the established group does not use persistence, decline to join thegroup. Likewise, a device indicating a desire and/or having a policyrequirement to join a group with persistence disabled may, in responseto determining that the established group does use persistence, declineto join the group. A device sending such an indication may do so priorto the determination of which device becomes the group owner (GO) forthe group. In some embodiments, if the device subsequently becomes GO,the device may use the outcome of the determination in block 702 todetermine whether persistence should be enabled for the group and maythen use this outcome to set a value (e.g. set the value to 1 or 0) of aPersistent Reconnect bit in the Group Capabilities Bitmap field that thedevice sends describing the P2P group capabilities. The value of thePersistent Reconnect bit may be set to 1 when the P2P device is hostingor intends to host a persistent P2P group that allows reconnectionwithout user intervention. Otherwise, the value of the PersistentReconnect bit is set to zero.

FIG. 8 illustrates a process for handling a device in a persistentgroup. A candidate device may transmit a PGI bit of zero in block 802which indicates that the candidate device does not desire a persistentgroup. If a group is established with persistence enabled despite thisdesire as in bock 804, the device may decide not to store persistentinformation as in block 806. This may apply in situations where althougha device is able to store persistent data, the device does not wish todo so and does not want to join a PPG. In that case, the device may berequired to renegotiate when re-joining the same group in the future asin block 808.

Other embodiments by which a GO determines whether persistence should beenabled are described below. FIG. 9 illustrates a process by which a GOdetermines persistence. FIG. 10 illustrates a process for by which a GOdecides persistence. When a GO establishes a group, there may not be amechanism available for it to receive an indication from another peerdevice within that group as to whether the group should be persistent.In such an instance, the GO's autonomous decision to establish a PPG (orto not establish a PPG) may not take into account thepreferences/policies of peer devices within the group.

FIG. 9 illustrates a flow chart for a device that subsequently becomesthe group owner (GO). Each of the devices in a group may provide anindication in block 902 (e.g. PGI) that allows the GO of thesubsequently formed group to determine if that group should bepersistent or non-persistent. In block 904, one of the devices of thegroup becomes the GO (e.g., by means of GO negotiation). In oneembodiment, the GO is selected based at least partially on theindications provided in block 902. The GO receives an advertisedindication (e.g. a PGI bit) from a candidate device intending (or notintending) to use group persistence in block 906. If the GO received anadvertisement from a candidate device, with a value of the PGI bit setto 0, the GO then establishes a group without persistence as in block910. Conversely if the GO received an advertisement from a candidatedevice with a value of the PGI bit set to 1, the GO may establish agroup with persistence as in block 908.

FIG. 9 illustrates a GO receiving an indication from one device.However, it will be appreciated that a GO may also receive indicationsfrom multiple devices and these indications may differ. In suchembodiments, the GO may need to determine if the group it creates willhave persistence based on a combinatorial rule such as a decision basedon what the majority of indications indicate, or a decision based onwhether at least one (or at least N) devices have expressed a particularpersistence preference. FIG. 10 illustrates such a modified flow chartfor a GO.

A device becomes a GO of a new group in block 1002. In becoming GO, theprocess may for example follow a GO negotiation algorithm or may followa modified version of this process, or may follow an alternativeprocess. If a group persistence preference (e.g. the PGI bit) withinthat GO device is set to a value of 1 as in block 1004, the groupbecomes a PPG in block 1006. In some embodiments, (e.g. if the PGI bitsent by the GO device is set to a value of 0 in block 1004), the GO maythen consider the indications of other candidate devices in block 1008with respect to their intent or desire to connect to a PPG (e.g. whetherthey are advertising their PGI bits equal 1). The GO may then decide toestablish a PPG in block 1006, or a non-persistent group in block 1010based on any appropriate algorithm taking into account the indicationsof other devices. In an alternative embodiment, the indications of otherdevices and its own preference will be used for determining persistence.Additional algorithms or embodiments for determining persistenceinclude: 1) majority voting; 2) a presumption to enable persistenceunless all devices indicate a preference otherwise (or no preference);and/or 3) presumption to disable persistence unless all devices indicatea preference otherwise (or no preference). Accordingly, FIG. 10establishes that the GO can determine persistence based on a number ofdevices within a group, while FIG. 9 established that a single peerdevice can be used to determine persistence.

FIG. 11 illustrates a process for determining a group owner (GO). Thedetermination of a GO may referred to as GO negotiation and may besubject to a GO negotiation algorithm for deciding the GO as discussedbelow. In block 1102, peer devices transmit PGI values, which are usedin the group negotiation in block 1104. In the example shown in FIG. 11(with two devices, A and B), if one device sets its PGI bit to 1, andthe other device sets its PGI bit to 0 in block 1106, the device withPGI=1 is elected as GO as in block 1108. If there is no clear outcomefor the GO based on the PGI bit values of candidate devices, analternative GO election method may be used as in block 1110. AlthoughFIG. 11 illustrates two peer devices, the process may be extended tomore than two devices.

For an alternative method in block 1110, the GO may be established basedat least partially on GO intent level as discussed above with respect toblocks 1008 and 1012 of FIG. 10. The higher a GO intent level, the morelikely a device is to become GO. In one alternative embodiment, a devicemay set its GO intent level in accordance with its desire to form/join apersistent or non-persistent group (e.g. as determined in block 1002).For example, the device might carry out the following steps: 1)determine a desire to join a persistent or non-persistent group; 2)(optionally) determine a GO intent level according to other inputs (maybe unrelated to persistence); 3) if the device desires to join apersistent group, increase the GO intent level; 4) if the device desiresto join a non-persistent group, decrease the GO intent level; 5)transmit the GO intent level; and 6) perform GO negotiation based on GOintent level. In some embodiments, the signaled GO intent level maydepend on the signaled indication for persistence (e.g. the PGI bit). Ifdifferent levels of desire are configured (e.g. preference vs. policy),the GO intent level may be modified by multiple different degreesdepending on the extent to which the device wishes to join a persistentor non-persistent group. In addition to a GO intent level, there may bea persistence intent level or persistence group intent level thatmeasures a device's desired intent to be part of a persistent group. Inone embodiment, the persistence intent level may the same as or similarto the GO intent level in terms of how the intent level is determined.The persistence intent level may be advertised or communicated prior tojoining a group and used in GO negotiation.

In an alternative embodiment, the setting of a PGI bit of a device maybe used directly within the GO negotiation either instead of, ortogether with, the transmitted GO intent values. For example, the PGIbit may be used as the basis of a tie-breaker if GO intent levelsindicated by two or more peers are equal. In this alternativeembodiment, the device may carry out the following steps: 1) determine adesire to join a persistent group; 2) (optionally) determine a GO intentlevel according to other inputs (may be unrelated to persistence); 3)(optionally) transmit the intent level; 4) transmit an indication of adesire to join a persistent or non-persistent group (i.e. a grouppersistence preference); and 5) perform GO negotiation based on (atleast) the indicated group persistence preference(s) as transmitted bydevice and peers and (optionally) based on intent levels.

FIG. 12 illustrates a process for advertising whether persistence isenabled for a group. An indication (e.g., a PGI bit) of grouppersistence may be advertised, by any group member, to a candidatedevice prior to a candidate device joining the group. The indication maybe similar to the PGI bit that signifies whether or not the establishedgroup is a persistent P2P group. Once a device becomes a GO of a newgroup as in block 1202 the GO determines if persistence is required orenabled for that group in block 1204. This determination may beaccording to FIG. 9. If the group is persistent, the device may set itsPGI bit value to 1 in future discovery advertisements and procedures inblock 1206. If the group is not persistent, the device may set its PGIbit value to 0 in future discovery advertisements and procedures inblock 1208.

FIG. 2 illustrates an embodiment where the wireless device 102communicates (pre-joining) with a plurality of groups. The selection ofa group by the wireless device may be based on indications advertisedfrom GOs for those groups. The indications may be the PGI bit and mayassist a candidate device in deciding which group to connect with. Insome embodiments, the device may, in response to receiving theindication(s) corresponding to the respective group(s), determine to notjoin any group. This may optionally include a step similar block 702 ofFIG. 7 wherein the device determines its preference for joining apersistent group.

FIG. 13 illustrates a process for a wireless device discovering P2Pgroups. The wireless device is a candidate device 202 identifying whichgroup to join. The device may attempt to join a group to determinewhich, if any, detected groups are using persistence, and (optionally)to select a group (or to select no group) from amongst those discoveredbased on the determined information. In block 1302, the device detects(e.g. by means of discovery mechanisms) the existence of two or moregroups that provide one or more services of interest to the device.Devices (such as the GO) within each group advertise whether persistenceis in use in that group (such as by means of transmitting a specificvalue of the PGI bit), and these indications of persistence are receivedby the candidate device in block 1304. In block 1306, the device mayevaluate the services available in each group. If the device determinesthat acceptable (or desirable) services are available in more than onegroup in block 1308, then the device selects and attempts to join (oneof) the group(s) for which persistence is enabled as in block 1312.

If no group explicitly indicates the use of persistence, the device mayselect a group for which no explicit indication is given. Similarly, ifthe device determined that it should join a group which does not usepersistence, the selection may be made by prioritizing those groupswhere persistence is indicated explicitly as not being in use. Forexample, groups may be prioritized as: 1) groups where persistence isexplicitly indicated as being in use; 2) groups where no explicitindication is made; and 3) groups where persistence is indicatedexplicitly as not being in use. If the device subsequently leaves (e.g.disconnects from, or is disconnected from) a PPG to which it previouslywas connected in block 1314, it may reconnect after some time passes. Ifneither group advertises persistent storage, then the candidate devicemay use an alternate means (e.g. a random tie break) to determine whichof the groups to connect with (if any) as in block 1310.

The systems and methods described above may be modified for backwardscompatibility with legacy devices. Legacy devices may automatically setany previously undefined or reserved bits as zero. There may need to bean additional indication (e.g. 1 bit) that indicates that persistence isset in another bit (PGI bit). For example, there may be a total of 2bits that are employed that include a “PGI bit valid” indication whichis set to 1 by a device supporting the PGI bit. The second bit would bethe indication itself (i.e. the PGI bit). Effectively the “PGI bitvalid” bit is an indication of a device's capability to support PGIsignaling and the pre-joining communications discussed above. A devicesupporting PGI may indicate that the PGI bit is not valid if it has nopreference regarding whether persistence is enabled for the group.Similarly, for an established group, a legacy device in the group willindicate “PGI bit valid=0,” while a device supporting the featureindicates “PGI bit valid=1.” This may avoid ambiguity as to whether thedevice is a legacy device not supporting the new PGI bit, or asupporting device indicating that persistence is not desired (or is notin use in an existing group).

The embodiments described above may allow a wireless device to determineand indicate whether it prefers to join a group for which persistence isenabled or to join a group for which persistence is disabled, prior togroup formation. The embodiments described may further allow a groupowner (GO) to take into account the desires/preferences/policies of itspeers when establishing a group, specifically with regards todetermining whether or not to enable persistence in the group. Thisavoids the GO storing credentials for devices which do not wish to usepersistence (and may therefore discard the group credentials on leavingthe group). Similarly, it may avoid the creation (or joining) of a groupwhich does/does-not use persistence in contradiction to a memberdevice's desire/policy and the subsequent departure of that device,resulting in wasted signaling and battery consumption. Other embodimentsmay enhance the GO negotiation process so that it is more likely that adevice wishing to enable persistence becomes GO, which avoids a devicewhich does not wish to use persistence from being expected/requested byits peers to enable persistence for the group. Other embodiments mayallow a device to determine whether persistence is used in an existinggroup, prior to joining that group which further allows a device i) todetermine whether or not to join a group, and/or ii) to preferentiallyselect a group operating in line with its preferences/policy.

The system and process described may be encoded in a signal bearingmedium, a computer readable medium such as a memory, programmed within adevice such as one or more integrated circuits, and one or moreprocessors or processed by a controller or a computer. If the methodsare performed by software, the software may reside in a memory residentto or interfaced to a storage device, synchronizer, a communicationinterface, or non-volatile or volatile memory in communication with atransmitter. A circuit or electronic device designed to send data toanother location. The memory may include an ordered listing ofexecutable instructions for implementing logical functions. A logicalfunction or any system element described may be implemented throughoptic circuitry, digital circuitry, through source code, through analogcircuitry, through an analog source such as an analog electrical, audio,or video signal or a combination. The software may be embodied in anycomputer-readable or signal-bearing medium, for use by, or in connectionwith an instruction executable system, apparatus, or device. Such asystem may include a computer-based system, a processor-containingsystem, or another system that may selectively fetch instructions froman instruction executable system, apparatus, or device that may alsoexecute instructions.

A “computer-readable medium,” “machine readable medium,”“propagated-signal” medium, and/or “signal-bearing medium” may compriseany device that includes, stores, communicates, propagates, ortransports software for use by or in connection with an instructionexecutable system, apparatus, or device. The machine-readable medium mayselectively be, but not limited to, an electronic, magnetic, optical,electromagnetic, infrared, or semiconductor system, apparatus, device,or propagation medium. A non-exhaustive list of examples of amachine-readable medium would include: an electrical connection“electronic” having one or more wires, a portable magnetic or opticaldisk, a volatile memory such as a Random Access Memory “RAM”, aRead-Only Memory “ROM”, an Erasable Programmable Read-Only Memory (EPROMor Flash memory), or an optical fiber. A machine-readable medium mayalso include a tangible medium upon which software is printed, as thesoftware may be electronically stored as an image or in another format(e.g., through an optical scan), then compiled, and/or interpreted orotherwise processed. The processed medium may then be stored in acomputer and/or machine memory.

In an alternative embodiment, dedicated hardware implementations, suchas application specific integrated circuits, programmable logic arraysand other hardware devices, can be constructed to implement one or moreof the methods described herein. Applications that may include theapparatus and systems of various embodiments can broadly include avariety of electronic and computer systems. One or more embodimentsdescribed herein may implement functions using two or more specificinterconnected hardware modules or devices with related control and datasignals that can be communicated between and through the modules, or asportions of an application-specific integrated circuit. Accordingly, thepresent system encompasses software, firmware, and hardwareimplementations.

The illustrations of the embodiments described herein are intended toprovide a general understanding of the structure of the variousembodiments. The illustrations are not intended to serve as a completedescription of all of the elements and features of apparatus and systemsthat utilize the structures or methods described herein. Many otherembodiments may be apparent to those of skill in the art upon reviewingthe disclosure. Other embodiments may be utilized and derived from thedisclosure, such that structural and logical substitutions and changesmay be made without departing from the scope of the disclosure.Additionally, the illustrations are merely representational and may notbe drawn to scale. Certain proportions within the illustrations may beexaggerated, while other proportions may be minimized. Accordingly, thedisclosure and the figures are to be regarded as illustrative ratherthan restrictive.

What is claimed is:
 1. A method in a wireless device, the methodcomprising: receiving, prior to group formation of a peer-to-peer (P2P)group, persistent information for the P2P group, wherein the persistentinformation comprises a Persistent Group Information field providinginformation about a persistency of the P2P group; and forming the P2Pgroup based on credentials subsequent to receiving the persistentinformation, wherein the wireless device enables persistency in the P2Pgroup if the Persistent Group Information field indicates support ofpersistency.
 2. The method of claim 1, wherein the credentials arestored and used for subsequent P2P groups with the wireless device,wherein the wireless device is configured to send a second persistentGroup Information field subsequent to enabling persistency in the P2Pgroup, and wherein the second Persistent Group Information field is sentto another wireless device that has not previously connected to the P2Pgroup.
 3. The method of claim 1, wherein the credentials are not storedby the wireless device if the wireless device has no intent to create apersistent group.
 4. The method of claim 1, wherein the Persistent GroupInformation field is part of a service-specific indication.
 5. Themethod of claim 4, wherein the service-specific indication is a Wi-FiDirect Services (WFDS) service.
 6. The method of claim 1, wherein grouppersistence is governed by a group persistent policy based on anApplication Programming Interface (API).
 7. The method of claim 1,wherein, if the Persistent Group Information field indicates non-supportof persistency, deleting the credentials after a connection has closed,and wherein, if the Persistent Group Information field indicates supportof persistency, advertising, to non-members of the P2P group,information indicating that persistency in the P2P group is enabled. 8.The method of claim 1, further comprising setting, by the wirelessdevice, an advertisement bit to a value indicating that persistency inthe P2P group is enabled, wherein the advertisement bit is advertised toa candidate device prior to the candidate device joining the P2P group.9. A wireless device, the device comprising: a memory; and a processorcoupled to the memory and configured by instructions stored in thememory to: receive, prior to group formation of a peer-to-peer (P2P)group, persistent information for the P2P group, wherein the persistentinformation comprises a Persistent Group Information field providinginformation about a persistency of the P2P group; and form the P2P groupbased on credentials subsequent to receiving the persistent information,wherein the wireless device enables persistency in the P2P group if thePersistent Group Information field indicates support of persistency. 10.The wireless device of claim 9, wherein the credentials are stored andused for subsequent P2P groups with the wireless device, wherein thewireless device is configured to send a second Persistent GroupInformation field subsequent to enabling persistency in the P2P group,and wherein the second Persistent Group Information field is sent toanother wireless device that has not previously connected to the P2Pgroup.
 11. The wireless device of claim 9, wherein the credentials arenot stored by the wireless device if the wireless device has no intentto create a persistent group.
 12. The wireless device of claim 9,wherein the Persistent Group Information field is part of aservice-specific indication.
 13. The wireless device of claim 12,wherein the service-specific indication is a Wi-Fi Direct Services(WFDS) service.
 14. The wireless device of claim 9, wherein grouppersistence is governed by a group persistent policy based on anApplication Programming Interface (API).
 15. The wireless device ofclaim 9, wherein, if the Persistent Group Information field indicatesnon-support of persistency, the wireless device delete the credentialsafter a connection has closed, wherein the credentials areauthentication credentials, and wherein, if the Persistent GroupInformation field indicates support of persistency, the wireless deviceadvertises, to non-members of the P2P group, information indicating thatpersistency in the P2P group is enabled.
 16. The wireless device ofclaim 9, wherein the persistent information is advertised, by the P2Pgroup owner in an existing persistent P2P group, to a candidate deviceprior to the candidate device joining the existing persistent P2P group.17. A non-transitory computer readable medium having stored thereonexecutable instructions for causing one or more processors to performoperations comprising: receiving, prior to group formation of apeer-to-peer (P2P) group, persistent information for the P2P group,wherein the persistent information comprises a Persistent GroupInformation field providing information about a persistency of the P2Pgroup; and forming the P2P group based on credentials subsequent toreceiving the persistent information, wherein persistency in the P2Pgroup is enabled if the Persistent Group Information field indicatessupport of persistency.
 18. The non-transitory computer readable mediumof claim 17, wherein the credentials are stored and used for subsequentP2P groups, wherein a second Persistent Group Information field is sentsubsequent to enabling persistency in the P2P group, and wherein thesecond Persistent Group Information field is sent to a wireless devicethat has not previously connected to the P2P group.
 19. Thenon-transitory computer readable medium of claim 17, wherein thecredentials are not stored by a wireless device if the wireless devicehas no intent to create a persistent group.
 20. The non-transitorycomputer readable medium of claim 19, wherein the Persistent GroupInformation field is part of a service-specific indication, wherein theservice-specific indication is a Wi-Fi Direct Services (WFDS) service.21. The non-transitory computer readable medium of claim 19, whereingroup persistence is governed by a group persistent policy based on anApplication Programming Interface (API).
 22. The non-transitory computerreadable medium of claim 19, wherein, if the Persistent GroupInformation field indicates non-support of persistency, deleting thecredentials after a connection has closed, wherein the credentials areused for authentication with the P2P group.
 23. The non-transitorycomputer readable medium of claim 19, wherein the executableinstructions for causing one or more processors to perform operationsfurther comprise a member of the P2P group sending, subsequent toenabling persistency in the P2P group, a second Persistent GroupInformation field to a peer wireless device prior to the peer wirelessdevice joining the P2P group, wherein the second Persistent GroupInformation field indicates that the P2P group is a persistent group.